Anti-static materials are used to remove static electricity or electrostatic charge, and an enhancement in charging with static electricity is associated with various problems in processing and using a variety of industrial products and materials. Charging with static electricity may cause attraction or repulsion of materials. In addition, an enhancement in charging with static electricity may cause attachment of waste or dust onto materials, thereby leading to manufacturing problems and pollution, and damaging performance of products.
An enhancement in charging of static electricity may be controlled by increasing electric conductivity of a material. This can be achieved by increasing ionic conductivity or electric conductivity. Typically, the accumulation of static electricity is controlled by adsorbing water molecules to increase electric conductivity. The adsorption is performed by, typically, adding water molecules to ambient air or using a water-absorbing anti-static agent, which is called a wetting agent. Most anti-static agents reduce electrostatic charges when charging with static electricity increases.
Known anti-static agents are, for example, organic amine and amide, aliphatic ester, an organic acid, a polyoxyethylene derivative, polyvalent alcohol, metal, carbon black, semiconductor, and various organic and inorganic salts. In addition, various surfactants may also be used, and they may be neutral or ionic.
Since various low molecular weight neutral anti-static agents have sufficiently high vapor pressure, such materials may be reduced in amounts by evaporation at high temperature, and thus, they are not suitable for use at high temperature. Various other neutral anti-static agents do not have sufficiently high thermal stability, so that they fail to perform their due functions under conditions for dissolving and processing a polymer and other high-temperature process conditions.
Various non-metallic anti-static agents are wetting agents that resort to adsorption and conductivity of water molecules to reduce charge. Accordingly, when humidity in the air is low, their effects are typically low. In addition, those anti-static agents are water-soluble, and accordingly, when materials are exposed to water molecules, the anti-static agents are easily removed. Accordingly, durability thereof is low.
Metal salts of inorganic, organic, and fluoro-organic anions are also suitable for use as an anti-static agent in a particular polymer composition. Due to costs and toxicity, and high affinity of an alkali metal cation, in particular, lithium with respect to water, alkali metal salts are the most commercially used. However, most metal salts do not have compatibility with polymers with middle or lower levels of polarity, such as polypropylene, polyester and polycarbonate. This incompatibility may decrease performance of an anti-static agent, may decrease physical properties of an anti-static agent to an unacceptable level, or may decrease transparency of finished polymer products to an unacceptable level. Ultimately, a metal salt for use as an anti-static agent is limited to a polymer matrix with high polarity or high hydrophilic property.
In response, the inventors of the present application searched for a quaternary ammonium salt compound that is suitable for use as an anti-static and anti-microbial agent and found that when a fiber is treated with a quaternary ammonium salt compound, static electricity of the fiber may be prevented or improved, thereby completing the present invention.